Research on Internet traffic conducted by various network companies and authorities shows that media content will take up 90% of the total Internet traffic in the future. Therefore, effectively storing and accessing the media content is a critical and hot issue in network technology research.
An economic way of storing the media content to meet the demands of large numbers of users is to use a high speed cache (cache mechanism, that is, copies of the media content are cached on cache devices having the storage function). The cache devices are generally distributed over the network. When a user requests the media content, the user only needs to access one or multiple cache devices storing the media content.
One problem is presented during using of the cache mechanism, that is, on which cache devices the copies of the media content are to be placed. Concerning this problem, the prior art proposes the following solution:
The cache devices on which the copies are to be placed are selected by minimizing the physical distance between the locations for placing the copies. This solution predicts, according to the popularity of the copies, the number of copies to be placed to balance the supply and the demand, and then selects several cache devices close to each other in terms of the physical location to place the copies.
However, the technical solutions in the prior art has the following problems:
In the prior art, the cache devices on which the copies are to be placed are selected by minimizing the physical distance between the locations for placing the copies and copies of the media content are placed on these cache devices. In practice, it is probable that no copies are placed on cache devices that are frequently accessed by users, and consequently users need to transit to other cache devices for accessing the copies, causing a longer delay when users access the media content.
Or, it is possible that copies of the media content are placed on cache devices that are seldom accessed by users. Consequently, an access rate of the copies is low, affecting storage space of the cache devices.